Need to work out how to implement drag and drop for individual objects.
This seems to be a good starting point.
https://stackoverflow.com/questions/24926028/drag-and-drop-multiple-objects-in-html5-canvas

Need to find a way of assigning a handler to individual objects ideally.
But using the way above may work..
It will just mean that the port of the original AS3 code from this chapter will be a little more awkward.


